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cool it
27-09-2005, 07:27 PM
Hi guys. I work for a company at the minute(leaving next week) We are in the process of installing a mitsi HI VRF. I have been with them about 2 months and they are not the best company I have worked for put it that way.
Anyway we installed the main pipe run and I posed the question as to where the branch pipes were.
They then said that we are going to make them !!!
I scratched my head. He then explained to me that we will get some reducers from say 2 1/4 to 7/8 then we put 7/8 in one end and put a 7/8 and a 5/8 coming outthe other end heat it up and squash it around the pipes then braze it up......
I personally didnt do any because I didnt want to get involved. I know that the branch pipes that you buy are made in a factory somewhere and probably had a lot of trial and error to get them perfect.
So what I am asking here is .......... if people spend a lot of money making these things precisely are the ones that they have bodged up gonna work?????????????

US Iceman
27-09-2005, 08:51 PM
From my experience these homemade attempts fail miserably.

I once found a refrigerant distributor for a TXV made from a section of copper pipe. One end of the pipe was brazed into the outlet of the TXV.

The other end of the pipe had 6 smaller pieces of tubing (all different lengths) brazed into this end with the opposite ends of the tubing feeding the coil. These different length tubes were the distributor tubes feeding the coil.

It did not work at all.

These are not qualified people. I don't blame you for leaving.

Peter_1
27-09-2005, 09:48 PM
1. For the Mitsubishi VRF's, we use an ordinary T as a branch. Mitusbishi knows this and they trust us.

2. A branch on a VRF is +/- the same as a branch on a supermarket pack.

3. Did you know that you can buy pre-made branches as a white, much cheaper poduct?

4. The way they made it, well... I disapprove this completely.

Temprite
27-09-2005, 10:23 PM
G'day Peter.

We use branch pieces when we install twin systems or larger multi systems (dont do much bigger stuff than that).

I thought that instead of the branch pieces that I could use a Y piece from our wholesaler or as you said a T piece as it is much cheaper.

When we went to a training session they showed us a video with water running through the branch fitting showing how the refrigerant flow would would be restricted if it was not installed correctly. I asked them about Y pieces and they claim that they will not work properly.

Thats what I expected them to say considering they are selling them.:)

martind
28-09-2005, 07:55 AM
Do not do this, I have experiences with this.
1. Sound problems - these homemade branches are in many cases very noisy, and then it is a real problem to fix it.
2. In many cases there were big problems with the capacity of the last units in the system - it did not cool properly.
3. With bigger diameters we had problems with firmness of the squeezed part. And it was with R407C, can you imagine what R410A could make.

Argus
28-09-2005, 09:42 AM
Martin is absolutely right.

The strength integrity of a 'home-made' squeezed joint is always suspect. It could fail at some point in the future and injure someone.

I would add that VRF equipment demands equal distribution of refrigerant through all the braches, apart from the furthest indexes being starved of flow, these joints add extra flow resistance to the entire circuit.

My undersatnding of the 'y' and 'comb' shaped distributors favoured by the (mainly) Japanese VRF manufacturers is that they minimise resistance and maximise flow rate. Furthermore they are designed to withstand the pressures and where necessary to comply with the PED.

I don't know about elsewhere, but there is a corporate liability in UK law where where safety is concerned.

But Cool It was right the first time. It is exceptionally poor practice whatever the reason.

.
________
Building (http://www.ford-wiki.com/wiki/Ford_Building)

frank
28-09-2005, 09:55 PM
I have a little video by Daikin showing the flow through the refnet joint but I'm not sure how to share it with you guys due to the video file size. Any ideas Webram?

cool it
29-09-2005, 05:29 PM
I have a little video by Daikin showing the flow through the refnet joint but I'm not sure how to share it with you guys due to the video file size. Any ideas Webram?
Hi frank it would be interesting to see this is it possible you could send it through msn messenger ? or even in a email?

frank
29-09-2005, 07:37 PM
Hi frank it would be interesting to see this is it possible you could send it through msn messenger ? or even in a email?
Sure - by e-mail no problem. send me your address privately if you wish